High-power fuel cells go portable

August 25, 2005By Mark PeplowThis article courtesy of Nature News.

Plug in your laptop to a cool hydrogen power source.

If you can't bear to be away from your laptop during that camping trip to deepest Borneo, help may soon be at hand. Lightweight generators powered by methanol are now on the market... for the rich, at least.

The device, designed to specifications for the US Army by the California company UltraCell, weighs just 1.3 kilograms when fuelled up and is the size of a novel. With a supply of 500 millilitres of methanol, the cell can chuck out 45 watts for a day, which is enough to power a laptop.

The cell and fuel together are half the weight of the lithium batteries needed to provide the same power.

Unlike traditional generators, fuel cells are totally quiet. And unlike batteries, they can be 'recharged' without being plugged into the wall.

Pocket converter

Companies such as Toshiba have come up with their own fuel cells for laptops. But most of these products run directly on methanol, giving them a relatively low power output for their weight.

UltraCell focused instead on turning methanol into hydrogen inside the device, which lets them pump out twice as much power. The difficulty is that 'reforming' methanol to hydrogen involves a chemical reaction that runs at about 280 °C.

"As the system gets smaller you really have to work hard to manage the heat," says Nigel Brandon, a fuel-cell engineer at Imperial College London.

UltraCell has managed to isolate the heat in their cell from sensitive components just centimetres away, and the whole thing is cool enough for you to put your hand on the casing.

"That was the real breakthrough," says William Hill, vice-president of marketing for Livermore-based firm, who demonstrated the device on 23 August at the Intel Developer Forum in San Francisco, California.

Hill won't share the secret of how their insulation system works. "That's the part no one else has been able to do," he says.

Better, smaller, cheaper?

The hydrogen fuel cell in the device is similar to others that are already on the market, with the added advantages of a better catalyst. This helps to keep down the production of carbon monoxide, a by-product that can clog fuel cells.

The model now on sale is "every bit as impressive as what the big players have been touting for four or five years and haven't shown us yet", says Jeff Morse, an engineer from Lawrence Livermore National Laboratory, California, who worked on earlier versions of the fuel cell.

With a price tag in the tens of thousands of dollars, the army may be the only customer willing to pay for portable power just now. But Hill says that it should cost mere thousands in a year's time, opening the market to emergency-rescue crews and others who spend long stints in the wilderness. Hill hopes prices will fall to hundreds of dollars as the technology improves, low enough to tempt adventurous campers.

UltraCell plans to develop an even smaller fuel cell that runs at 25 watts, which would be sufficient for a low-power laptop. Hill says this lighter device should be much cheaper, and will be available from the end of 2006.